INTRODUCTION Investigations of bone stiffness and strength based on continuum finite element (FE) models have big advantages in terms of computational cost when compared to micro FE models. A nonlocal elastoplastic constitutive law with damage that leads to softening has recently been developed for the compressive behavior of trabecular bone [1]. Mechanical tests on human trabecular bone biopsi...

Two types of measurement are presented that relate molecular events to macroscopic behavior of F-actin networks. First, shear modulus is measured by oscillating an embedded microbead. Second, a microbead is translated at constant rate and transitions in the resisting force are observed. The loading rate dependence of the force at the transitions is similar to that of the molecular unbinding for...

Hydrogen atoms have a wide variety of effects on the mechanical performance of metals, and the underlying mechanisms associated with effects on plastic flow and embrittlement remain to be discovered or validated. Here, the reduction in the plastic flow stress (softening) due to hydrogen atoms in solute-strengthened metals, previously proposed by Sofronis et al., is demonstrated at the atomistic...

A cusp catastrophe model is presented and the necessary and sufficient conditions leading to landslides are discussed. The sliding surface is assumed to be planar and is a combination of two media: medium 1 is elastic-brittle or strain-hardening and medium 2 is strain-softening. The shear stress-strain constitutive model for the strain-softening medium is described by the Weibull’s distribution...

Metallic glasses are known to have a remarkably robust yield strength, admitting Weibull moduli as high for crystalline engineering alloys. However, their postyielding behavior is strongly varying, with large scatter in both flow stress levels and strains at failure. Using x-ray tomography, we reveal how strain-dependent internal evolution of shear-band cavities underlies this unpredictable res...

In this work, we use the rule of mixtures to develop an equivalent material model in which the total strain energy density is split into the isotropic part related to the matrix component and the anisotropic energy contribution related to the fiber effects. For the isotropic energy part, we select the amended non-Gaussian strain energy density model, while the energy fiber effects are added by ...

This paper presents nonlinear finite element (FE) models to predict time- and temperature-dependent responses of shape memory polymer (SMP) foams in the large deformation regime. For first time, an A SMP foam constitutive model is implemented ABAQUS FE package with aid a VUMAT subroutine thermo-visco-plastic behaviors. phenomenological reformulated adopting multiplicative decomposition gradient...

In this paper, in situ experiments have been designed using the full-field deformation technique of Digital Image Correlation (DIC) to characterize non-uniform shrinkage in thermoplastic polymers commonly used in traditional and emerging molding processes. These experiments are capable of characterizing the differences in strains that develop due to thermal gradients and stiction as the polymer...

Artificial cemented sand test samples were prepared by using ordinary Portland cement (OPC) as the cementing agent. Through uniaxial compression tests and consolidated drained triaxial compression tests, the stress-strain curves of the artificial cemented sand with different cementing agent contents (0.01, 0.03, 0.05 and 0.08) under various confining pressures (0.00 MPa, 0.25 MPa, 0.50 MPa and ...

The main mechanism of the cellular pattern which forms at the surface of a thin layer of a cohesive granular material submitted to in-plane stretching has been identified as the "strain softening" arising from the features of grain-grain interactions. We perform measurements of the strain field associated with such structures by using a correlation image technique and additionally characterize ...